Together with several partners, researchers from Siemens Corporate Technology (CT) and experts for large electrical drives at Siemens Industry Drive Technologies are investigating the use of silicon carbide (SiC) as a diode material in power electronics in place of pure silicon. Such an approach could reduce inverter energy losses by as much as 15%, Siemens says.

Along with improved efficiency, the researchers also believe that use of the SiC diodes will enhance the reliability and safety of the inverters. Other benefits of SiC power electronics—which have been of wide interest for a number of years—include a large reduction in the size, weight, and cost of
the power conditioning and/or thermal systems.

Large machines such as pipeline pumps and compressors for natural gas liquefaction systems and ship propulsion systems are currently powered almost exclusively by electric motors that are operated at variable speeds. These motors require frequency inverters that convert the normal power line frequency (e.g., 50 Hz in Europe, 60 Hz in the US) into a variable frequency that ranges from zero to approximately 200 Hz. The inverters function much like a dimmer for controlling the brightness of a light source. The Siemens research project seeks to substantially increase the efficiency of these inverters.

Siemens says it is carrying out pioneering work in the project, as comparable SiC high-voltage diodes operating in the medium-voltage range have not been used anywhere in the world to date.

The recently launched research project is receiving approximately €1.7 million (US$2.2 million) in funding from the German Ministry of Education and Research.

The MV-SiC project was launched in June 2010 and will run until April 2013. It is part of the “Power Electronics for Improved Energy Efficiency” initiative, which in turn is a component of the German government’s High-Tech Strategy and the “Information and Communication Technology 2020” (ICT 2020) program.

One of the goals of the latter is to achieve greater energy efficiency and reduce pollutant emissions through the application of new developments in power electronics systems. Along with Siemens, ICT participants include The Technical University of Dresden, Infineon, Curamik Electronics, and SiCED Electronics Development.